ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
207 
Onchnesoma Steenstrupii.*— Mr. A. E. Shipley states that tho 
anatomy of this, the smallest of Sipunculids, is more simple than that 
of other members of the group. The head is much simplified, for there 
are no tentacles, hooks, collar, eyes, or pigment in the skin ; there is no 
vascular system, no spindle-muscle, and no giant-cells in tho brain. 
The retractor muscle is single, as is also the nephridium, and the brain 
is not bilobed. Whether this state of things is rudimentary or vestigial 
we cannot decide till something is known of tho development of this 
worm ; perhaps some characters are of one, and others of the other kind. 
Mr. Shipley is of opinion that the tentacles and closed vascular 
system, when present in Sipunculids, are not of importance for respira- 
tion, but that tho vascular system extends the tentacles, which, on their 
side, create currents which bring food to tho mouth. Tho chief respi- 
ratory organ is probably the intestine, for it has very thin walls, and 
exposes a largo surface to the coelomic fluid which bathes all the organs 
of the body except the brain. 
j8. Nematlielminthes. 
New Genera of Nematodes, f — Mr. N. A. Cobb founds a genus Onyx 
for a rouud worm allied to Dorylaimus, which he calls 0. perfectus ; it 
is common in the Bay of Naples. One of its characteristics is the 
possession of a pharyngeal bulb, the function of which is, by longitudinal 
contraction, to protrude the contained spear. The action — somewhat 
unique — of the various organs of the head and neck during feeding is as 
follows: — The lips are thrust forth and applied to the organism whose 
juices are to be sucked; the lips are made to adhere by suction exerted 
in the muscular posterior portion of the oesophagus. The spear is made to 
glide forward through its guide, and to pierce the surface held by the 
lip. Suction and swallowing aro effected by means of the muscular 
posterior oesophageal swelling. A distinct muscular bulb is unknown in 
Tylenchus, Aphelenchus, Dorylaimus, or other spear-carrying genera. 
The new genus Dipeltis is found for Ennplus cirrhatus of Eberth and 
two new species found at Naples and off Ceylon. The peculiar oral 
plates described by Eberth are really a hitherto unknown form of tho 
lateral organs ; each is an ellipsoidal structure nearly as wide as the 
head, and with a thickened margin. The author takes the opportunity 
of describing Dorylaimus latus sp. n. found in roots and stems of grass 
at Sydney. 
American Intermediate Host of Echinorhynchus gigas.J— Dr. C. 
W . Stiles remarks that Melolontha vulgaris and Cetonia aurata , the two 
insects that, in Europe, are regarded as tho intermediate hosts of 
Echinorhynchus gigas, are absent from America, and yet the parasite is 
frequently found in American hogs. By feeding the grubs of Lachno- 
sterna arcuata with the eggs of the Echinorhynchus, ho caused them 
to be infected with numbers of larval Echinorhynchi ; from one grub 
he took no less than 300 parasites six weeks after feeding. All the 
grubs examined before the feeding experiment were free from the para- 
* Quart. Jouru. Mier. Sci., xxxiii. (1892) pp. 233-49 (1 p].). 
+ l’roc. Linn. Soe. N.S.W., vi. (1891) pp. 143-8 (6 figs.). 
J Zool. Anzeig., xv. (1892) pp. 52-4. 
