ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 653 



cells among the basal prolongations of which we find nerve-fibrils, of 

 sensory, and of goblet-shaped glandular cells. 



Stalked Crinoids of the 'Challeng^er' Expedition.* — Dr. P. 



Herbert Carpenter has published in the ' Challenger ' reports a very 

 full monograph of the morphology of Crinoids generally, and au 

 extensive account of the stalked forms. 



The first, or morphological, portion deals with the skeleton gene- 

 rally, and the mode of union of its component joints ; in the second 

 chapter the stem and its appendages as seen in the Pentacrinidae, 

 Bourgueticrinidfe, and Hyocrinidae are considered, and the differences 

 in the three groujjs are pointed out ; the author thinks that " the 

 resemblance and ' probable homology ' which Prof. Perrier sees be- 

 tween the arms and the root of a Crinoid are .... forced in the 

 extreme " ; for the former are merely extensions of the body, while 

 the branches of the root have a very different structure, or, in other 

 words, that of the stem, as is indeed allowed by Perrier himself. 

 The terminal faces of the stem-joints of Hyocrinus are interesting as 

 being of the same nature as those of the Apiocrinidfe and many of 

 the Palaeocrinoids. 



In the third chapter the calyx, and in the fourth the rays are 

 dealt with ; the characters of the ijinnules of Palaeocrinoids are dis- 

 cussed, and the view of Wachsmuth and Springer that the alternate 

 plates of Ci/athocrinus are rudimentary pinnulas is objected to, 

 analogy being apparently confused by them with homology. The 

 three functions of pinnules are, it is pointed out, that of protecting 

 the fertile i)ortions of the genital glands, of serving as respiratory 

 organs, and of aiding in alimentation ; in Cyathocrinus all these 

 functions might have been performed by the branching arms. 



The division by Ludwig of the coelom into an intervisceral and 

 circumvisceral portion is regarded as convenient, but it is pointed out 

 that in some species — such, for example, as Antedon eschrichti among 

 the Comatulids, and in the stalked Crinoids — it is difficult to fix a 

 definite boundary between them. The oral plates which, formed in 

 Pentacrinoid larvae, are absorbed during development, are retained 

 throughout life by Holopus, Hyocrinus, Shizocrinus, and Thaumato- 

 crinua. W yville Thomson's name of perisomatic skeleton is adopted 

 for " the basal and oral plates, the anal plate, the interradial plates, 

 and any other plates or spicules which may bo developed in the 

 perisome of the cup or disk," while that of " visceral skeleton " is 

 used to denote the " numerous spicules and networks of limestone 

 which occur more or loss plentifully in the bands of connective tissue 

 that traverse tlie visceral mass of tlie Comatuhc" and the more or 

 less regular plates which arc found within the disk of Pentncrinus ; 

 these are formed of a calcareous network interpenetrated by an 

 organic basis, wliich is of the same nature as in the joints and arms. 



In the sixth chapter the minute anatomy of the disk and arms is 

 dealt with, and the author states that his extended observations on 



♦ Koport of the Voyage of II. M.S. 'Challenger' — Zoology, xxxii. (1884) 

 440 pp. aud 09 pie. 



