280 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
(2) In both types of eyes the rods arise at the inner ends] of the epi- 
dermic cells originally turned away from the light. 
(3) In the Hauptaugen an inversion of the retina brings the rods 
in front of the nuclei. 
(4) In the Nebenaugen the epithelium forming the retina shows 
only a slight insinking, and the rods lie permanently behind the nuclei of 
the optic cells. 
New Stridulating Spider.* * * § — Mr. E. I. Pocock describes, under the 
name of Cilharoscelus Kochii g. et sp. n., a stridulating Therapliosid 
spider from South America. Hitherto such spiders have only been de- 
scribed from tropical Africa, the Oriental region, and Trinidad. The 
stridulating organ in the new form is placed between the coxae of the 
palp and of the first pair of legs, and is similar to that of the Eumeno- 
phorinae, but less specialised in structure. Mr. Pocock thinks it likely 
that this spider is identical with that described and figured by Koch as 
My gale rosea Welck. 
e. Crustacea. 
Chelae of the Lobster.f — Dr. Hermann Stahr has studied in detail 
the structure of the great claws in 52 specimens of Homarus vulgaris , 
with special reference to the teeth and tubercles of the grasping surfaces. 
He finds that in the great majority of cases each individual bears chelae 
of two different types ; tbe one chela being long, slender, and furnished 
with regularly alternating teeth of various sizes, and the other broad 
and heavy, bearing somewhat irregular tubercles. Those of the former 
type bear also numerous tasting hairs. Not infrequently both claws 
may be similar and of the toothed type, while rarely forms occur which 
are transitional between the two types. As the chelae in Astacus ap- 
proach the toothed type of Homarus , while those of Brachyura are 
tuberculated, the author believes that the former are phylogenetically 
older. As to the function of the two chelae in the lobster, the author 
believes that the toothed claw is a decorative ornament, and is also used 
in hunting, while the tuberculated claw is used for grasping and crushing. 
British Isopod Chelifera4 — Canon Norman publishes a very useful 
list of this group, which comprises the two families of Apseudidae and 
Tanaidae. He records twenty-three British species, as contrasted with 
the seven described by Bate and Westwood. The paper includes an 
extensive bibliography. 
Annulata. 
Development of the Capitellid8e.§— Prof. Hugo Eisig supplements 
his monograph by a detailed and fully illustrated account of the develop- 
ment of the Capitellidae. The paper is divided into four main divisions : 
(1) The development of embryo and larva ; (2) the development of the 
organs and germ-layers ; (3) discussion of the origin of Annelids ; (4) 
observations on segmentation and the germ-layers. The first part closes 
with a complete table of the segmentation and of the fate of the various 
cells, and is throughout too detailed to admit of abstraction. The 
* Ann. and Mag. Nat. Hist., iii. (1899) pp. 347-9. 
t Jenaische Zeitschr. Naturwiss., xxxii. (1898) pp. 457-82 (2 pis. and 1 fig.). 
X Ann. and Mag. Nat. Hist., iii. (1899) pp. 317-41. 
§ M.T. Zool. Stat. Neapel, xiii. (1898) pp. 1-292 (9 pis. and 4 figs.). 
