850 -SUMMARY OF CUERENT RESEARCHES RELATING TO 



OpMurids of the 'Gazelle.'*— Prof. Studers finds that ten of the 

 fifty-eight species of Ophiurids collected during the voyage of the 

 ' Gazelle ' are new to science ; five others have been already named and 

 their diagnoses published ; the names of the new forms are Pectiniira 

 semicincta, Opliiolepis affinis, Oiilnopyrgus saccharatus, OpMoghjpha stel- 

 lata, Ampliiura modesta, A. congensis, Opliiocliiton lymanni, OphiacantJia 

 gracilis, Ophiothrix smamgdina, Opliioscolex prolifer. Some account of 

 Ophiothrix peter si n. sp. has already been given,f when attention was 

 directed to the remarkable sexual dimorphism exhibited by it, the 

 coloration of the sexes being very ditferent. Some of the observa- 

 tions are of importance as bearing on our knowledge of the geo- 

 grai^hical distribution of the members of this group; Ophiomi/xa 

 flaccida was found at the Cape Verde Islands, and no specific differ- 

 ences could be detected between it and the West Indian specimens. 

 The marsupial pouch of Opliioglijplm hexadis is described as a large 

 thin-walled sac, lined by a layer of nucleated cells ; in each, two or 

 three embryos are to be found. 



Ccelenterata. 



Coelenterates of the Southern Seas.+ — The fourth of E. v. Len- 

 denfeld's communications is devoted to an account of a new genus, 

 Eucopella, the forms of which are small and ephemeral, while they 

 are devoid of tentacles or gastric cavity. The persons of the species 

 examined — E. campanularia—iall under three groups ; there is the 

 nutrient person, the blastostyle, and the medusfe. The first of these 

 is the person which exhibits the least deviation from the original 

 Hydroid stock ; its structure is described in detail, and among the in- 

 teresting points noted we find that the hypostome is described as a 

 funnel-shaped tube, which connects the mouth with the entrance into 

 the gastric cavity ; the same definition applies to the oesophageal tube 

 of Actinice, and, in fact, if the new polyp were to swallow its hypo- 

 stome, it would possess a true oesophageal tube ; the ectoderm of this 

 hypostome is distinguished by some essential points from that of the 

 same part in other Hydi'oids, for it is formed of high cylindrical 

 epithelial cells, and contains cnidoblasts, which have within stinging 

 capsules similar to those found in the tentacles. In the endoderm we 

 find a large number of small ganglionic cells, connected together into 

 a central nervous organ. In addition to these, there is a continuous 

 layer of well- developed subepithelial circular muscles, which give to 

 this layer a high grade of diftercntiation. 



If we put aside the sxipposition that the just-mentioned ganglionic 

 cells have been originally derived from the ectoderm, and have made 

 their way through the supporting lamella, we must suppose that the 

 central organ of the nervous system of the Eucopella-'polj-ps has been 

 derived from the endoderm. This offers a new support to the lately 

 developed hypothesis of the complete equivalence of the germinal 



* Fremde Abh. Akad. Berl., 1882, 37 pp. (3 pis.). 



t Zool. ADzeig., iii. (1880) p. 546. 



X Zeitschr. f. Wiss. Zool., xxxviii. (1883) pp. 497-583 (6 pis.). 



