TRANSACTIONS OF SECTION D. 5O5 
has been confirmed, e.g., as to the injuriousness of house-sparrow, wood-pigeon, 
and carrion-crow, and as to the beneficial activity of hedge-sparrow, fieldfare, 
lapwing, and plovers. On the other hand, there are several cases in which the 
results up to the present do not altogether confirm previous opinions; thus the 
diet of the black-headed gull and the common gull shows a striking resemblance 
to that of the useful lapwing. It is much to be desired that this inquiry, and 
others like it elsewhere, should be continued for a term of years, and the 
co-operation of farmers and others interested is solicited. 
4. Chordeuma obesum, a New Parasitic Copepod Endoparasite in 
Asteronyx loveni. By Professor Hector F. E. JuNGERSEN. 
This form is a common parasite in the interior of Asteronyx loveni (which 
itself is fixed to living Pennatulids and Gorgonians, in the Skagerrak always to 
Funiculina quadrangularis). With few exceptions I found it present in every 
specimen of Asteronya examined." The parasite is enclosed in a thin membranous 
capsule formed by the host, and these galls may be found practically in every 
part of the interior except inside the gonads and digestive cavity. ‘Sometimes 
they are so numerous that the whole interior of the host seems made up by the 
parasites ; in such cases the gonads of the Asteronyx seem not to develop."* Each 
gall contains either a male or a female Copepod.” If the latter is ripe the gall 
encloses also its eggs and brood, and very often a male (seldom two), and empty 
spermatophores. The eggs do not form ovisacs, but are loosely cemented 
together in one large mass, distending the one end of the gall, filling every space 
left at the posterior part of the mother. The male, if present, is completely 
imbedded in the egg-mass. Both embryonic development and most of the post- 
embryonic metamorphosis occur inside the gall. As larve of Cyclops shape 
the young leave the gall, subsequently either settling in the same host, thus 
augmenting the stock of parasites already present, or they leave by way of the 
bursal openings to infest other individuals of Asteronyx, making their way into 
these through the same portholes. In both cases the larva itself by its 
hooked maxillz to some point of the tissues lining the burse, and causing them 
to produce the gall. The larval cuticle is now cast off, and the parasitic form 
ensues. No more moultings take place, but the Copepod and its gall continue 
for a while to grow considerably, the parasite at the same time undergoing 
slighter modifications in the shape of the body and its appendages, and develop- 
ing its inner structures; finally the full size and sexual maturity are attained. 
The adult female is 4-5-3 mm. in length, sausage-shaped; composed of a 
cephalon, four thoracic segments, and an unsegmented post-abdomen. The cepha- 
lon carries in front short, unsegmented antennules, with two blunt terminal 
processes and a small ventro-lateral spine. Immediately in front of the mouth 
is a pair of slender papilliform appendages, the antenna (an antennal gland 
being present). Close behind the mouth are the mazille, the largest and the 
only segmented appendages found, consisting of three segments, the terminal one 
forming a hook. Myes, mandibles, and mazillule are wanting. 
Each of the thoracic segments carries a pair of short, conical, parapodia-like 
feet; in young specimens the terminal part-—like that of the antenne—is hairy. 
Each foot represents the outer branch of the biramous larval swimming foot. 
In young, immature specimens a rudiment of the inner branch may be preserved 
on the second, third, or fourth pair. Between the second and third thoracic 
segments is a deep constriction : here the membranous wall of the gall fits tightly 
in, thus forming two compartments, the posterior containing the hind part of 
the female, the egg-mass and eventually the male. The anterior part of the post- 
abdomen is as broad as the thorax, carrying on the ventral surface the genital 
openings; on each side it sends out a large rounded process. The remaining 
part of the post-abdomen forms a short, narrow appendix, sending out a blunt 
conical process, dorsally at the base and terminating in two short bifurcate 
spines. The whole post-abdomen represents three segments. There is no anus 
and no trace of an intestine inside the post-abdomen. The digestive apparatus 
consists of a capacious stomach, ending blindly in the last thoracic segment, and 
