632 
SUMMARY OP CURRENT RESEARCHES RELATING TO 
the forms investigated have a complex excretory system. In Sticho - 
stemma grsecense there was found to be only one pair of nephridia in 
small specimens, while the larger had sometimes eight at one side of 
the body and nine at the other. The nephridial tubules formed a fine 
network through the body, the fine branches ending internally in well 
defined “ flame-cells.” A similarly complicated nephridial system was 
found in Geonemertes , where ten excretory pores were counted on either 
side of the body. During the course of his detailed observations on the 
gland-cells of the cerebral organ of Sticlio stemma, the author came to 
the conclusion that the disappearance of the nucleolus from an actively 
secreting cell shows that it is a reserve from which new chromatin 
may he manufactured. 
Incertae Sedis. 
Larval Development of Cheilostomata.* — M. Louis Calvet has 
studied this in numerous species, e.g. of Bugula , Scrupocellaria , F lustra, 
and Lepralia. ^blastula with a reduced blastocoele is followed by an 
epiholic gastrula, in which four initial endoderm cells enter the segmen- 
tation cavity. The endoderm retains its primitive character through 
the whole of the larval development ; the mesoderm is not differentiated 
until shortly before hatching. In the larvae of the viviparous species 
there is a neuro-muscular system quite comparable to that of Cyphonautes 
compressus and the larvae of Ctenostomata (Flustrellidae, Alcyonididae), 
but there is no digestive tube. A “mesodermic thickening” occurs 
similar to that which Prouho has described in Ctenostomata. 
Origin of Polypide in Marine Ectoprocta.f— M. Louis Calvet has 
studied the much-discussed origin of the polypide in the oozoids, young 
blastozoids, and adult blastozoids, of numerous species. 
Only in the oozoids does the polypide arise as an invagination of 
the zooecial walls. In other cases the polypide begins as a solid mass, 
which secondarily becomes diploblastic and hollow. Only in the oozoid’s 
polypide are there elements representing the three germinal layers. 
In the blastozoids, the polypide has a mesenchymatous origin, from 
elements which in the young blastozoids are derived from the ectodermic 
epithelium, and in the adult blastozoids from the funicular tissue. In 
these cases, therefore, the differentiation of the three germinal layers is 
not recognisable. 
Echinoderma. 
Amputation of Disc-covering in Ophiurids.* — Dr. C. Ph. Sluiter 
begins an interesting note by referring to Prof. Jeffrey Bell’s description 
of a remarkable ophiurid from Brazil (1888) in which the covering of 
the disc was lost, and the dorsal surfaces of the most proximal arm-joints 
were strangely affected. Sluiter believes that this form was probably 
identical with or nearly allied to Ampliiura grisea Lym. But he is more 
concerned with the occurrence of a similar loss of the disc-covering in 
Ophiocnida echinata Ljn. (Lym.), in which he suspects that a normal 
amputation occurs periodically, probably in connection with repro- 
duction. It is also suggested that the covering of the disc and the 
genital organs are regenerated after the reproductive season. 
* Coraptes Rendus, cxxvii. (1898) pp. 79-81. f Tom. cit., pp. 194-7. 
1 Tijdschr. Nederland. Dierk. Yer., v. (1898) pp. 303-10 (2 figs.). 
