Microanatomy of the cubopolyp,Tripedalia cystophora (Class Cubozoa)

Abstract

ABSTRACT. The microanatomy of a cubopolyp (polypoid stage of Cubomedusae) is described for the first time. The 0.5-1.0 mm long polyp of Tripedalia cystophora has an oral cone with special lip cells at the mouth. Next is a baggy calyx occasionally followed by a slender stalk. The basal region is surrounded by a thin periderm. A single row of teI~tacles is at the oral cone/calyx junction. The mesoglea is thin and non-cellular. The muscular system of the ectoderm is composed of smooth longitudinal epitheliomuscular cells in the oral cone, tentacle, stalk and calyx. The calyx ectoderm also sends longltudinal muscle fibers into the mesoglea. The mesogleal muscle fibers seem to contain paramyosin and perhaps are doubly innervated: one set of neurites for contraction and one for relaxation. A circular endodermal system of filaments, probably actin, is found in aI1 regions. The tentacles have a solid core of a single row of endodermal cells capable of phagocytosis. The ectodermal tip is swollen with longitudinally aligned nematocysts. The distal part of the tentacle contains striated ectodermal myofibers. The nervous system is unique in having an endodermaI/ectodermaI nerve ring pair at the calyx/oral cone junction. Ganglion cells are not apparent. Presumed sense cells have complicated microvilli and no flagellar rootlet. A cell fitting the description of a neurosecretory neurone is especially prominent in the oral cone's endoderm. It has a major process reaching the coelenteron. Round macrogranular cells corresponding to the amoebocytes of the Scyphozoa and Anthozoa are found. There are no interstitial ceils. The oral cone's flagellated endoderm is made up of mucous cells, cells with small dark granules, cells with large granules and rodlets in the cytoplasm, and a few absorptive ceils. The calyx endoderm is very thick (120 #m) a~d is made up of flagellated absorptive, mucous and granular cells. In~ested food is transformed into basal droplets. 4 size and shape types of the microbasic eurytele category make up the cnidome. The largest nematocyst types are found at the tentacle's tip. Like a hydropolyp, the cubopolyp lacks gastral septa and is in other features radially symmetrical. Like a scyphopolyp, the cubopolyp has mesogleal muscles and no interstitial cells. Unique histological features are the nerve rings and tentacular striated muscles.

Mesodermal anatomies in cnidarian polyps and medusae

“…The polyps lack mesenteries and retractor muscles. They have no putative mesodermal elements apart from striated muscle-like cells in the ectodermal tip of the polyp tentacles (Chapman, 1978), which, however, apparently lack the typical banding pattern observed in medusa and bilaterian striated muscles Schuchert et al, 1993). The transformation of the polyp into a medusa leads to the formation of a bell structurally related to the hydromedusa bell.…”

Morphologie und Ultrastruktur der KoralleCornularia cornucopiae (Anthozoa, Octocorallia)

“…Besonders auff~illig ist dabei die strukturelle Ubereinstimmung der basalen Lage, die eine B~inderung aufweist, deren Abstand bei Nematoden 20 nm (Koch, 1980), bei Comularla cornucoplae 23 nm betrafft. Es handelt sich bei den Nematoden, den Anneliden (Garrone, 1978) (Blanquet & Lenhoff, 1966) sowie im Axialskelett der Gorgonarie Leptogorgia virgulata (Goldberg, 1974;Leversee, 1980) und der Pennatulatie Veretlllum cynomorlum (Franc et al, 1976) (Mackie, 1960;Knight, 1970;Bouillon & Levi, 19711 Marcum & Diehl, 1978), den Scyphozoa (Chapman, 19691 Hentschel & Hiindgen, 1980) und den Cubozoa (Chapman, 1978) aul Marcum & Diehl (1978) unterscheiden bei den Hydrozoen drei Typen: lebende, sich entwickelnde Desmocyten, stoffwechselinaktive, funktionstiichtige Desmocyten und abgestorbene Restdesmocyten.…”

Metamorphosis of the polyp ofTripedalia cystophora (Cubozoa, Carybdeidae) into the medusa

“…Gabriele Laska, Bonn. Die bereits fortgeschrittene Arbeit ist damit die notwendige Fortsetzung der histologischen und elmikroskopischen Untersuchung des Polypen durch Chapman (1978).…”