g Echinoderma. 



were spatulate or lappet-like flaps, each supported by a, calcareous axis articulated 

 to a plate in the body. These marginal flappers were separated into five zones 

 by the tentacles of the water- vascular system, and served as locomotive organs. 

 - The young of many Ophiurids (Ophiocoma, Ophiothrix &c.) have paired hook- 

 like spines on the terminal segments of the arms ; while in Astrophyton and other 

 genera similar spines occur on different parts of the arms, serving as grasping- 

 organs. The embryonic ones are perhaps homologous with the nectospines of 

 Asterias. 



Sllliter has observed the habits of some of the Echinoderms from the Java 

 seas which he has kept in aquaria. Fhyllacanthus imperialis never climbs the 

 sides, but hides itself by day, and creeps long distances over the coral sand at 

 night. The many varieties of Diadema setosum occur in large numbers closely 

 packed together among the corals. The next most common form is Echinometru 

 lucunter which creeps about in the corals, though not boring into them, as stated 

 by Studer. At -chaster typicus also occurs in great numbers, and creeps about by 

 night under' a layer of sand, with which it covers itself. Culcita schmideliana will 

 creep up the vertical sides of the aquarium and change its shape remarkably in so 

 doing. When inverted, it takes ten minutes to regain its position, expanding first 

 the dorsal, and then the ventral surface into a spherical form. It feeds on different 

 Urchins, including Echinometra lucunter. in spite of its formidable spines. Among 

 numerous examples of Asterina cephea was one with 4 and one with 6 arms. 



II. Felmatozoa 

 (including Crinoidea, Cystidea, and Blastoidea 1 " . 



See also Bury, supra, p 4, Cuenot. supra, p 6, Hamann, supra, p 1. Korschelt 

 (>), supra, p 3, Mac Miinn (V 2 ), supra, p 6, and Semon ''), supra, p 5. 



Hamann describes the nervous system of Crinoids as consisting of three 

 parts, two of which are mesodermal, while the third, that of the ambulacra, is 

 purely epithelial. The central organ of the dorsal system is the envelope of 

 the chambered organ. In Antedon rosacea this consists of closely set fibrils with 

 small and bipolar ganglion cells scattered everywhere through it. Larger cells, 

 both bipolar and multipolar, occur on the dorsal side, especially at the points of 

 origin of the nerves to the cirri and arms. The latter are quite solid, having no 

 central cavities, with small, bipolar cells uniformly distributed, while the larger, 

 multipolar cells form a peripheral layer , and are particularly abundant at the 

 ends of the transverse commissure in the axillary radial. The nerve within the 

 arm has a covering of granular wander cells on its dorsal side, and in the centre 

 of each joint of arm or pinnule it enlarges and gives off four nerves, two dorsal 

 and two ventral. The latter supply the muscles and give off branches to the epi- 

 thelium, in which also the dorsal ones terminate. The same is the case in the 

 cirri. The central organ of the ventral system is the pentagonal ring around 

 the mouth discovered by Jickeli [see Bericht for 1884 I p 172]. It lies in the 

 cutis, at about the same level as the water-vascular ring, and contains large 

 ganglion cells, both bi- and multi-polar. It gives off nerves to the oral tentacles 

 and a pair of radial trunks at the sides of each water-vessel, besides others which 

 ramify in the integument and send branches into the bands of connective tissue 

 traversing the coelom. The radial trunks contain large nerve cells and send fibrils 

 to the ciliated epithelium of the water-pores , the tentacles with their papillae, 

 and the musculature of the water- vessels. These form the parambulacral network 

 of Carpenter [see Bericht for 1885 I p 186]. The dorsal and ventral systems 



