Echinoderma. 



centre is incomplete, so that there are no definite indications either of the month 

 or of the ambulacra. 



V. Koenen i' 1 , 2 ) gives an account of the morphology of the skeleton in Dado- 

 crinus gracilis and in 5 species of Encrinus. They are at least as closely related to 

 the Neocrinoids as to the Poteriocrinidae , and should not therefore be classed as 

 Palaeocrinoids, as has been done by Wachsmuth & Springer [see Bericht for 1886 

 Ech. p 7]. The visceral cavity probably extended up to the level of the lowest 

 pinnules and was covered by a flexible perisome as in recent Crinoids. In D. 

 gracilis this extended downwards between the rays to the level of the first 

 radials , and bore interradial perisomic plates. These occur in every interradius 

 and not merely on the anal side, as supposed by Wachsmuth & Springer. Two 

 tetraradiate examples of E. liliiformis are mentioned, and also some malforma- 

 tions of the arms which seem to have been due to Myzostoma. 



Gu'rich concludes from the condition of several specimens of Encrinus gracilis, 

 that it had a plated ventral perisome which extended downward in the interradial 

 spaces to the level of the first radials. 



Carpenter ( 5 ) gives a general account of the arrangement of the skeletal plates 

 in Crinoids and Blastoids. 



Ratte adopts the views of Carpenter respecting the hornologies of the dicyclic 

 base, and gives a revised description of the structure of Tribrachiocrinus in accor- 

 dance with the nomenclature of Wachsmuth & Springer. 



Carpenter () points out that the body-cavity of a Blastoid did not communicate 

 directly with the exterior like that of a Starfish; though Perrier's proposed clas- 

 sification of the Echinoderms implies that it did so [see Bericht for 18S(i Ech. p3]. 



Wachsmuth & Springer point out that the spiracles of Pentremites conoldcus are 

 not closed by plates , as supposed by Shumard ; and they do not believe that the 

 rigid spines forming the pyramid above the vault in P. sulcatus and its allies are 

 the proximal pinnules , as suggested by Etheridge & Carpenter. In all the known 

 species of Elaeacrinus the summit is formed by a central plate surrounded by 6 or 

 more proximals ; and the same arrangement is generally visible in Qrophocrinus, 

 Schizoblastus and Granatocrinus. In Caryocrinus there is a large central piece sur- 

 rounded by S others, 3 radial and 5 interradial. The 5 plates covering the peri- 

 stoine of Allagecrinus and Haplocrinus are interradials and not orals, as supposed 

 by Carpenter [see Bericht for 1886 Ech. p 8]. 



III. Asteroidea. 



See also Hamann( 1 , 3 ), supra, p 3, Hartog, supra, p3, Kohler, supra, p 1, ;and 

 Preyer, supra, p 4. 



Bell ( 2 ) points out that the most extreme Asterid known, though presenting a 

 remarkable general resemblance to an Echinoid , is morphologically less like it 

 than a typical Asterid is. 



According to Cuenot (*) the aboral ring of the young Asterid (= perihaemal ring, 

 Ludwig) is at first empty and gives off 2 caeca in each interradius. But the ovoi d 

 gland which is at first simple, and is enclosed in the axial sinus communicating 

 with this ring, sends processes into it which extend completely round and give off 

 branches into the interradial caeca. From the cells lining these branches the ova 

 and spermatoblasts are developed. The rudiments of the genital organs are thus 

 derived directly from the ovoid gland which is the source of the amoeboid cor- 

 puscles of the blood-spaces. The ovum is therefore morphologically homologous 

 with a blood corpuscle, amoeboid cells sometimes appearing in the interior of the 

 ovary, but never in the testis. The so called intestinal vessels of Hoffmann and 



