1902.] SPIDERS OF THE GENUS DESIS. 99 



advisable to point out what are the type-species to which these 

 names must I'emain affixed : — 



The type of the genus Desis is the species represented by the 



specimens (? in the Paris Museum) desci'ibed by Walck- 



enaer as Desis dysderoides. 

 The type of the genus Dandridgia is the species represented by 



the specimen in the British Museum desciibed by White 



as Dandridgia dysderoides. 

 The type of the geniis Rohsonia is the species represented by 



the .specimen in the Rev. 0. P. Cambridge's collection 



described as Rohsonia marina. 

 The type of the genus Paradesis is the species represented by 



the specimen in the British Museum described as Paradesis 



tuhicola. 



1. Desis martensi L. Koch. 



Desis martensi L. Koch, Die Arachn. Austral, -p. 347, pi. xxix. 

 figs. 2-29 (1872) ; T. G. Workman, Malaysian Spiders, no. 11, p. 74 

 (1896). 



Log. Singapore ; Pulo in the Java Sea. 



The British Museum has specimens of this species from Singa- 

 pore {Major Archer, Lieut. Kelsall, and P. F. Bedford). 



Lieut. Kelsall's specimens, which were forwarded by Mr. H. N. 

 Ridley in 1890, were accompanied by the following information : — 

 '' From the holes bored in the coral rock by a sj^ecies of Litlio- 

 phaga. From Buran Durat Reef near Blacku Mati Island. 

 Nea,rest land | mile distant. Reef uncovered at half-tide." 



The announcement of the discovery by Dr. von Martens that this 

 spider is ti'uly marine elicited the following expression of opiniqn 

 from Dr. 0. L. Koch, to whom the specimens were submitted for 

 description : — " [The sjjider] was collected by [Dr. von Martens] 



on coral-reefs at Singapore The species is remarkable in 



that it has established itself in these reefs, which are only tem- 

 porarily uncovered by the sea That the species discovered 



by Dr. E. von Martens and Dr. Johswick can really, like our 

 indigenous Argyroneta aquatica CI., live under water, is to me 

 doubtful in the highest degree, for it is wanting in the outward 

 visible signs of the breathing apparatus which corresponds to such 

 submarine mode of life, and which has been anatomically de- 

 monstrated in Argyroneta aquatica^. It also speaks against it, 

 that yet another species of spidei', an Aitus, was found on the 

 same coral-reefs, and we may assume with all certainty that this 

 is a true terrestrial form. I opine that these spiders, perhaps in 

 former times, were floated in an accidental manner from the land 

 to these reefs and now live in the holes of the coral- bank, within 

 which they withdraw at the time of flood, and which they close 



1 This is scarcely true, for, as I have pointed out (Ann. & Mag. Nat. Hist. (6) xvi. 

 p. 143), Desis martensi has the tracheal slit large and well in advance of the 

 spinners, though not so far forwards as in A. aquatica. 



