2 Echinoderma. 



Prouho, H., Recherches sur le Dorocidaris papillata et quelques autres Echinides de la Me- 

 diterranee [completed], in: Arch. Z. Exper. (2) Tome 5 p 289380 T 1426. [19] 



Sarasin, C. F. & P. B., 1. Die Langsmuskeln und die Stewart' schen Organe der Echinothu- 

 riden. in: Z. Anzeiger 11. Jahrg. p 115 117 Fig. [22] 



, 2. Uber die Niere der Seeigel. ibid, p 217218. [22] 



, 8. Uber die Anatomie der Echinothuriden und die Phylogenie der Echinodermen. in : 



Ergebnisse Nat. Forschungen Ceylon 1. Bd. p 83154 T 1017. [4, 22] 



Semon, R., Die Entwickelung der Synapta digitata und die Stammesgeschichte der Echino- 

 dermen. in: Jena. Zeit. Naturw. 22. Bd. p 175309 T 612. [3, 16, 24] 



Wagner, R., Uber Encrinus Wagneri Ben. aus dem unteren Muschelkalk von Jena, in: Zeit. 

 D. Geol. Ges. Berlin p 822828 Fig. [11] 



I. Morphological and Physiological Works of a General Character. 



Cuenot ( 2 ) describes the refringent coloured granules found in the corpuscles of 

 the coelom and vessels of Asterids and Ophiurids as consisting of a substance 

 different from haemoglobin, which he calls haemoxanthin. It occurs in Man 

 and other Vertebrates, Arthropods, Worms and Mollusca; and it is of the nature of an 

 albuminogenous ferment which converts the peptones produced by the digestive 

 ferments into soluble but non-diffusible albuminoids. These can then remain in 

 the coelom and vessels of an Echinoderm without passing out through any of the 

 excretory organs. This haemoxanthin is not respiratory in function, the oxygen 

 dissolved in the sea water being sufficient for this purpose. The amoebocytes 

 and their contained granules are produced in the lymphatic glands, viz. 

 the ovoid gland for the coelom and vascular system, the Polian vesicles for the 

 ambulacral system, and the genital cords for the generative organs. Neither in 

 the Ophiurids nor in the Asterids can the ambulacral system be regarded as 

 aquiferous, the water-pores of the former being excessively reduced. The pre- 

 sence of amoebocytes within the ambulacral system shows that there can be neither 

 inward nor outward current. The water-tube is merely a morphological relic, 

 without function in the adult, though it may have had one in the embryo. 

 Asterids and Ophiurids constitute two distinct types of Echinoderms, their most 

 highly differentiated representatives being Asterias glacialis and Ophiothrix rosula 

 respectively. Ophiurids closely resemble young Asterids in the characters of their 

 digestive, ambulacral, and vascular systems, though their nervous system is more 

 highly developed. The Euryalids present a more perfect development of some 

 organs than the Ophiurids, e. g. the madreporite, the vascular cavities of the 

 ovoid gland and gullet, and the nervous branches to the latter. The Asterids, 

 Ophiurids, and Urchins are closely similar in the early postlarval condition ; but 

 in their subsequent development the Asterids have followed the common phylum 

 most closely. 



According to Barrels the stem of the Crinoid larva represents the pre-oral 

 lobe in those of other Echinoderms. In normal Comatulae the body or calyx is 

 terminal, as regards this lobe, while in other Echinoderms it is lateral, a condition 

 which occurs abnormally in the Cbma&//a-larva as a reversion to the primitive 

 mode of metamorphosis. In Asterids and Echinids the right side of the larva be- 

 comes the dorsal face of the adult, and the left side becomes ventral ; while in C. 

 the ventral and dorsal sides correspond to those of the adult, though the ultimate 

 position of the peritoneal sacs is the same as in other Echinoderms. In the ab- 

 normal C. larva the position of the vestibular iuvagination corresponds to that of 

 the amniotic cavity in the left half of the subumbrella in the Urchin-larva ; the 

 water-pore is also left and dorsal ; the dorsal calcareous plates correspond in both 



