732 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
in tlie hepatic cells are then described. In the food-canal the blood 
loses all traces of red corpuscles, and forms a homogeneous reddish- 
brown mass, sometimes with crystals. Batelli supplements Pagen- 
stecher’s vague description of the Malpighian tubules, and describes 
the tracheal system which is genetically integumentary. A stigma is 
morphologically derivable from a group of hairs. The Ixodidse have 
no eyes, nor apparently any dermaptoptic sense, but there are various 
seemingly sensitive sette on the appendages. 
Post-embryonic Development of Acarida.* — Dr. P. Kramer has 
studied Diplodontus filipes Duges and Nessea fuscata C. L. Koch. He 
distinguishes in the developmental history of Acarida (1) a Tarsonemus 
type in which a hexapod larva — in adult form — leaves the egg; (2) a 
Trombidium type (Trombidiidas and Hydrachnidse) in which an octopod 
nymph is interpolated between the larval and the adult form ; (3) a 
Tyroglyphus type (Sarcoptidae, Tyroglyphidee, Gamasidae, Demodicidae) 
in which two nymph stages occur, and (4) an Oribates type (Oribatidae) 
in which there are three nymph stages. 
A Hermaphrodite Spider. | — Dr. Ph. Bertkau describes a species of 
Lycosa which exhibited the epigyne of a female and the swollen palp of 
a male, and had degenerate reproductive organs apparently most like 
diseased testes. His list of casually hermaphrodite Arthropods now 
includes 361 forms — 9 Crustaceans, 3 Arachnids, 349 Insects. 
Development of Limulus longispinis.J: — Mr. K. Kishinouyo has a 
preliminary note on the development of this King-Crab. About nine 
days after fertilization a blastodermic thickening comparable to the 
“ primary thickening ” already described by the author in the Spider, 
may be seen on the ventral surface of the egg. Its indifferent cells 
separate into ectoderm and mesoderm and form the commencement of the 
ventral plate. About the fourteenth day the mesoderm is divided into 
a number of transverse metameres, and, almost simultaneously, into two 
lateral parts. The endoderm is represented by the yolk-cells, which 
remain in the interior of the egg. 
The segments of the cephalic lobe and the first appendage are primi- 
tively cut off from the anterior end of the ventral plate as one segment ; 
all the appendages are post-oral in origin. The coelomic cavity is not 
produced in the segments of the second, third, or fourth appendages ; the 
cephalic lobe and the segment of the first appendage have a common 
cavity which developes along the sides of the stomodseum, and extends 
through the yolk to the dorsal part. In each of the segments posterior 
to the fifth a pair of coelomic cavities appear which extend over and 
envelope the yolk ; they give rise to a dorsal longitudinal median lumen 
(the dorsal circulating vessel) and many lateral slits (ostia). The 
mesoderm belonging to the second, third, and fourth appendages plays no 
part in the formation of the dorsal vessel. 
In Limulus there is a distinct line of demarcation between the dorsal 
and the ventral surfaces. The cephalothorax, as in Trilobites, is com- 
posed of five lobes — a median, and two laterals on either side. In both, 
* Arch. f. Naturgesch., lvii. (1891) pp. 1-14. f Tom. cit., pp. 229-38 (1 pi.). 
X Zool. Anzeig., xiv. (1891) pp. 264-6. 
