ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 217 



Asterid from Great Depths.* — E. Perrier describes under the 

 name of Gaulaster pedunculatus a remarkable starfish, taken by the 

 ' Travailleur,' which is provided with a dorsal peduncle, altogether 

 comparable, in position, to the stalk of young Comatulse, and of adult 

 fixed Orinoids. It is pointed out that while the Crinoids [Pelmatozoa 

 of Leuckart] are always fixed for some period of their lives, it is 

 interesting to find that, among the non-stalked forms, the apparently 

 oldest class may sometimes present a similar arrangement. The two 

 specimens were of unequal size, and the largest had a greater radius 

 of only 5 mm. ; in both, the apex of the interbrachial arc is occu- 

 pied by a sort of cleft, provided with papillee, and separating the 

 marginal plates of the adjacent arms ; the clefts are prolonged on to 

 the dorsal side of the disk, where they have a double row of spines, 

 which converge towards the base of the dorsal appendage. 



The marginal plates are not very evident, and are, as in Ctenodiscus, 

 arranged in only a single row ; there are five of them to each arm. 

 The tubercular madreporic plate is placed in one of the interbrachial 

 clefts. The ambulacral tubes have no suckers, and are arranged in 

 two rows, but there are only eleven pairs of them. The dentary 

 plates are simple scales, which fuse at their free extremity, and are 

 prolonged into a kind of conical unpaired tooth. The dorsal integu- 

 ment is soft, and seems to be without plates of any kind. The dorsal 

 appendage, which is 2 mm. long, is cylindrical, flexible, and granu- 

 lated on its surface. In the younger of the two specimens we find 

 at its base four large calcareous plates, arranged in cruciform fashion, 

 and each bearing a small spine ; a fifth plate, which is opposite to 

 the madreporite, clearly belongs to the same cycle. Five other and 

 smaller plates are set in the free angles formed by the first five. The 

 resemblance between these and the ten plates which form the peri- 

 proct in the Echinoidea, and those which make up the calyx in the 

 Crinoids is, clearly, very striking. In addition to this, it may be ob- 

 served that the young of Lejpty chaster, discovered by the ' Challenger,' 

 which are developed in a marsupial pouch, are attached to its walls 

 by the centre of their dorsal surface. On the other hand, the 

 rosette of plates is an embryonic character, and this is in agreement 

 with the view that the Asteroidea are derived from the Crinoidea. 

 Young Asterids and young Brisingce have dorsal plates which, as is 

 now well known, are arranged like those of the calyx of Crinoids ; 

 those of the first row, which become converted into the odontophores, 

 cannot be made out in Gaulaster. The new form is evidently near 

 Ctenodiscus, which has a slight dorsal tubercle, perhaps homologous 

 with the appendage of Gaulaster. 



Coelenterata. 



Cyclical Development and Relationships of the Siphonophora f 



— Dr. Carl Chun finds that in the cyclical development of the species 

 called by him MonopJiyes primordialis there are five stages : 1. Planula. 



* Comptes Eendus, xcv. (1882) pp. 1379-81. 



t SB. K. Preus. Akad. Wiss., 1882, pp. 1155-72 (1 pi.). Ann. and 3Iag. Nat. 

 Hist., xi. (1883) pp. 155-69. 



