186 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
families in larger divisions ; Prof. Sars recognizes eight or nine families. 
In regarding the interrelations of these he has made use of the chelifori. 
In one group they are entirely wanting, except in the larva ; in a second 
group they are always "well developed, and in the third they are present 
in young post-larval stages, but afterwards disappear more or less com- 
pletely. The following classification is proposed : — 
Order I. Achelata. 
Fam. 1. Pycnogonidm. Gen. 1. Pycnogonum. 
„ 2. Phoxichilidae. Gen. 2. PJioxichilus. 
Order II. Euchelata. 
„ 1. Phoxichilidiidae. Gen. 1. Phoxichilidium. 
Gen. 2. Anoplodactylus. 
„ 2. Pallenidae. Gen. 3. Pallene , Gen. 4. Pseudopallene , Gen. 5. 
Cordylochele. 
,, 3. Nymplionidae. Gen. 6. Nymphon, Gen. 7. Chsetonymphon , 
Gen. 8. Boreonymphon. 
Order III. Cryptochelata. 
Fam. 1. Ammotheidae. Gen. 1. Ammotliea. 
„ 2. Eurycydidae. Gen. 2. Eurycyde , Gen. 3. Ascorhynchus. 
,, 3. Pasithoidae, Gen. 4. Colossendeis. 
e. Crustacea. 
Eyes in Blind Crayfishes.* — Mr. G. H. Parker has examined the 
eyes of Cambarus setosus, a blind crayfish from caves in Missouri, and 
has compared them with those of C. pellucidus from the Mammoth Cave. 
He finds that both species still have the optic ganglion and nerve ; the 
latter ends in the hypodermis of the retinal region, but the mode of its 
termination has not yet been discovered. In G. setosus the retinal 
region is represented only by undifferentiated hypodermis, composed of 
somewhat crowded cells, but in C. pellucidus there is a lenticular 
thickening, in which there are multinuclear granulated bodies ; these 
appear to be degenerated clusters of cone-cells. The author confirms 
the results of Leydig, so far as they go, but is led to doubt the accuracy 
of Packard's observations. 
Cirolanidse and other Isopods.j — Herr H. T. Hansen gives an 
account of the Cirolanidm, Corallanidm, and Alcironidm, and refers 
briefly to the Barybrotidae, iEgidm, and Cymothoidae. He has studied 
thirty-four species, of which twenty-four are new. Perhaps the most 
important part of his memoir is the description of the mouth organs, 
their forms and movements, and their adaptation to various modes of life, 
e. g. in connection with incubation in many females. It is on the nature 
of these organs that he bases his classification, with this advantage 
among others that the great distinctions can be readily recognized with 
* Bull. Mus. Comp. Zool., xx. (1890) pp. 153-62. 
t Skrift. K. Danske Yid. Selsk., v. (1890) pp. 239-426 (10 pis.). 
