392 SUMMARY OF CURRENT RESEARCHES RELATING TO 



animals seem to show that protocytes are first observed as spots in the 

 egg, which become more and more distinct, or as spindle-figures, or as 

 aggregations of chromatin granules ; in the first case the eggs are either 

 living or have been only slightly acted on by reagents ; the third case is 

 probably the typical one, and if granules should be seen arranging them- 

 selves in a spindle, the second case would fall under it. It may be laid 

 down as a law that the free formed primitive nuclei arise from the non- 

 nuclear protojilasm first by the appearance of chromatin spheres, which 

 gradually crystallize out from the plasmatic magma. These spheres either 

 arrange themselves into a regular spindle-figure or fuse directly into a 

 protokaryon. The evidence against the spindle arising directly from the 

 germinal vesicle appears to the author to be complete. He is also of 

 opinion that the law, " omnis nucleus e nucleo," will be shown to be 

 contrary to the facts of the case. This lengthy essay, in which the 

 observations of the author are given in the utmost detail, and shown to 

 be often confirmatory of what has been discovered in other groups, con- 

 cludes with some observations on the relations of the non-nuclear ovum 

 to fertilization, and on the disappearance of nuclei in division and in 

 adult cells. 



E. Crustacea. 



Post-embryonic Development of Telphnsa fluviatilis.* — Dr. F. 



Mercanti finds that when the embryos of Telphisa fluviatilis escape from 

 the egg they are at a somewhat advanced stage of development, for they are 

 in the Megalopa condition, and have the eyes already stalked and the 

 ambulatory appendages completely developed. The author describes the 

 changes undergone by the limbs : the abdomen of the young is remarkable 

 for being more like that of the adult male than of the female. The 

 history of the development of T. fluviatilis has some points of resemblance 

 with that of Astacus fluviatilis ; but the most striking likeness is between 

 the young Telphusa and adult examples of the fossil Pseudotelphusa 

 speciosa from the miocene deposits of Oeningen. Dr. Mercanti's com- 

 parison of these two species leads him to adopt the theory of Prof. 

 Capellini, that the latter is an ancestral form of the species now living. 



Crustacean Parasites of Phallusia.t — M. P. Gourret has found seven 

 parasites in the branchial cavity or cloaca of Phallusia mammillata and 

 P. mentula from the Gulf of Marseilles ; they are all crustacean. Of two 

 known species, Doropygus (NoiopheropJiorus) papilio and D. (N.) elongatus, 

 there are two varieties, called respectively massiliensis and maculatus. 

 Pinnotheres Marioni sp. n. differs remarkably in the two sexes. There are a 

 few notes on Pontonia phallusise. The larvfe of a new species of Cryptoniscus 

 were observed, in which the body was fusiform, the sides of the abdominal 

 segments were prolonged into spines, one pair for each of the first two 

 rings, and two pairs for the others ; the lower antennae carry two 

 flagella, one of which is much reduced ; the gnathopods are not forceps- 

 like, and the dactylopodites were simple hooks. Leucothoe spinicar^a and 

 Lichomolgus forficula complete the list. 



' Challenger' Brachyura.j — Mr. E. J. Miers confines his report on the 

 Brachyura collected by H.M.S. ' Challenger ' to the systematic aspect of the 

 subject ; the groups richest in new genera and species are the Oxyrhyncha 



* Arch. Ital. Biol., viii. (1887) pp. 58-65. 

 t Comptes Kendus, civ. (1887) pp. 185-7. 



X Reports of the Voynge of H.M.S. •Challenger,' Monograph xlix. (1887) I. and 

 3G2 pp., 29 pis. 



