1887] Zoology. QI 
only describes the new species of the groups Apoda and Pedata, 
but adds a series of short accounts of all the forms known. Up to 
scarcely any from beyond two hundred fathoms. Now we know 
number met with at five hundred fathoms, and some that 
are abyssal. Thus Cucumaria abyssorum occurs from fifteen hun- 
dred to two thousand two hundred and twenty-three fathoms, 
Synapta abyssorum at two thousand three hundred and fifty 
fathoms, Pseudostichopus villosus from thirteen hundred and seven- 
ty-five to two thousand two hundred, while Holothuria thomsoni 
has been dredged from depths ranging from eighteen hundred 
and seventy-five to two thousand nine hundred fathoms. Some 
species have a wide bathymetrical eager individuals resid- 
ing at depths of from five hundred to sev n hundred fathoms 
presenting no notable differences from e living near the 
shore. 
M. H. Koehler maintains that in the Ophiuridæ the madreporic 
gland communicates by a cana with the lower or vascular peri- 
buccal ring, much as in the Echini. The internal epithelium of 
the intestine of the Ophiuridæ is very thic 
M. Gauthier maintains that the plates of the apical region of 
-echinids cannot be depended upon as characters for the delimita- 
tion of genera and species. He gives numerous figures of the 
variations in the apical plates of Hemiaster, from his own obser- 
vations with the microscope, to prove this. The disposition of 
these plates, notably that of the madreporic plate, often exhibit 
the variations relied on to establish species and genera. 
Vermes.—fecampia erythrocephala is a parasite in several Dec- 
apoda, and has been studied by M. Giard. arcinas m@nas is 
most commonly infested with it when young. It lives in the 
body cavity, and is often bent into a U form. Some crabs have 
several parasites. Sometimes it is hidden in the liver. If is 15 
mm. long, with a red head, and white, slightly rose-tinted 
cylindrical body. When sexually mature it leaves its host, 
crawls on the rocks, usually on its side, and soon builds a cocoon 
from threads secreted by the cutaneous glands. The cocoon is 
most dense upon the inside, becomes brittle by contact with the 
sea- water, and communicates by a narrow opening with the sur- 
rounding medium. ithin the posterior part of the cocoon 
the site deposits its rose-tinted eggs enveloped in a gelati- 
nous substance. The Fecampia itself has lost much of its bulk, 
and the snowy tint has disappeared. This transformation takes 
par at the end of August, at which period the females of C. 
nas lay their eggs. 
ea —The “ Challenger” Expedition collected one hun- 
dred and two species or well-marked varieties of Compound 
Ascidians. These are described by Professor W. A. Herdman in 
