ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
25 
prolongation of tlie cell, but may contract in any direction according to 
the stimulus, and the position of the nucleus is variable. 
^Morphology of Blood-corpuscles.* — Mr. C. S. Minot distinguishes 
the blood-corpuscles of Vertebrates as red cells, white cells, and 
plastids ; the last name is applied to the non-nucleated corpuscles of 
adult Mammals which are completely new elements, peculiar to the class, 
and not derived either from white or red corpuscles ; they were first 
described by Schafer, whose results have lately been confirmed by 
Kuborn. Their essential characteristic is that they arise intracellularly 
and by differentiation of the protoplasm of the vessel-forming cells. 
The red cells have three chief forms, the primitive of which does not, 
perhaps, persist in any adult Vertebrate ; the second form obtains in the 
Ichthyopsida, and the third in the Sauropsida. The author distinguishes 
(a) blood with single cells ; that is the first stage in all Vertebrates, when 
the blood contains only red cells with a small quantity of protoplasm ; 
( b ) blood with two kinds of cells, red and white ; the red cells have 
either a large, coarsely granulated nucleus as in the Ichthyopsida, or a 
small darkly staining nucleus as in Sauropsida and embryonic Mammals ; 
and (c) plastid blood, without red cells but with white cells and red 
plastids ; this is found only in adult Mammals. 
B. INVERTEBBATA. 
Parasites of Mola rotunda.t— Prof. Leidy reports a great number 
and variety of parasites from this Sunfish. Chief among them was the 
large Lernean, Penella filosa , which hung in great clusters from the root 
of the dorsal and other fins ; they were from five to nearly seven inches 
long and had one to three inches buried in the flesh of the fish. To 
many of these were appended the barnacle, Conchoderma virgatum , and they 
were also more or less profusely covered with colonies of the Hydroid 
Polyp Eucope parasitica. The other Crustacean parasites were Cecrops 
Latreillii , Lsemargus muricatus, and Dinematura serrata. 
Gliding on the skin was the circular Trematode Tristoraum Rudol- 
phianum , and in the intestine was Distomum pedocotyle which appears to 
be new ; the body is cylindrical, narrowest in front, with vertical 
bothria larger than the mouth and projecting in advance to an extent 
equal to the body. The soft, yellow liver of the fishes was throughout 
pervaded with the tape-worm Anthocephalus elongatus. 
Mollusca. 
o. Cephalopoda. 
Notes on Cephalopods.J — Dr. A. Appellof commences with a de- 
scription of a new genus of CEgopsida, which he calls Chthenopteryx ; 
its fins consist of a series of muscular filaments, which are connected at 
their base by an extremely thin and transparent membrane. The appa- 
ratus for closing the mantle consists of a cartilaginous piece placed 
on either side of the base of the funnel, and having in the middle an 
extremely delicate groove ; a cartilaginous ridge corresponding to this 
* Anat. Anzeig., v. (1890) pp. 601-4. 
f Proc. Acad. Philadelphia, 1890, pp. 281-2. 
t Bergens Museums A arsbere tiling for 1889 (1890) No. iii., 34 pp. and 1 pi.. 
