626 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Parthenogenesis in Spiders.* — Herr N. Damin records what he 
believes to be the first known case of parthenogenesis in Spiders. In 
the spring of 1891 he placed two living specimens of Filistata testacea 
in two separate tubes ; of these, one moulted twice in 1891 and once in 
1892 ; on the 8th July, 1892, it spun a cocoon and laid eggs, as unfer- 
tilized Spiders often do ; on the 27th July the author opened the cocoon, 
and, contrary to all his expectation, found sixty-seven young. The 
young were alive on the 1st March of this year, and had already 
moulted once. Few, if any, observers have found the male of F. testacea 
on the continent of Europe, but it still remains to be decided whether 
the parthenogenesis of the females is an occasional, or a regularly 
recurrent, phenomenon. And, of course, the observations open up the 
other question, Is parthenogenetic development found in any other 
Spider ? . 
Hew British Acarus.f — Mr. A. H. Michael gives an account of a 
new genus of Tyroglyphidse from Cornwall ; it was first observed in the 
water-weed Cladophora fracta, and it is proposed to call it Lentungula 
algivorans. The great peculiarity and interest of the form are to be 
found in the tarsi and claws ; the tarsi of the two front pairs of legs are 
very powerful, and form efficient climbing organs ; the claws of the same 
pairs of legs are mounted on long flexible peduncles which spring from 
the sides of the tarsi and are capable of being flexed at the will of their 
possessor. Most nearly allied to Hericia , the new genus is distinguished 
not only by the characters already mentioned, but by the terminal 
position of the anus, and the absence of sexual dimorphism. 
Brain and Sense-Organs of Limulus.J — Hr. W. Patten deals at 
considerable length with the morphology and physiology of these parts 
of the nervous system of Limulus. Healing first with the sense-organs, 
he urges that we can reduce the whole system of them either to isolated 
sense-cells or sense-buds, or aggregations of the same. In the young, 
sense-buds are found in all parts of the body and are everywhere alike ; 
afterwards they degenerate, or they become olfactory, gustatory, or tem- 
perature organs; the resemblance of these buds to ommatidia is so 
striking that both must be included in the same category. 
The author next deals with the morphology of the Arthropod brain, 
and asserts “ that after we have torn off the deceptive Arthropod mask 
that disguises Limulus we discover that the nervous system, with all 
its complex and intricate modifications, shows, as a whole, a profound 
structural similarity to that of Vertebrates.” Compared with the light 
thrown by the King-Crab on the phylogeny of Vertebrates, Ascidians, 
Balanoglossus , Nemerteans, Annelids explain nothing. Dr. Patten truly 
says that, if the Arachnid theory of the origin of Vertebrates be true, 
many current views on phylogeny, ontogeny, and important problems 
in Comparative Anatomy are based on false conceptions and must be 
revised. 
* Abh. Zool.-Bot. Ges. Wien, xliii. (1893) pp. 204-6. 
f Proc. Zool. Soc. Lond., 1893, pp. 262-7 (1 pi.), 
t Quart. Journ. Micr. Sci., xxxv. (1893) pp. 1-96 (5 pis.). 
