20 



D. alata, Java Sea : Thousand Islands (Aurivillius). 



D. equina. East coast of Malay Peninsula: Trengganu (Lanchester). 



D. Nierstraszi, Malay Archipelago, different Stations, see later! 



D. Tydemani, near Saleyer, see later ! 

 ? D. pellucida, Indian Ocean (Darwin), Oriental species with fairly extensive distribution (Anxandale). 

 ? D. Grayi, Tropical, Indian or Pacific Oceans (Darwin). 



D. Wcderi, Off Great Kei Island, see later! 



D. Versluysi, Malay Archipelago, different Stations, see later ! 



D. orthogonia, Malay Archipelago, different Stations, see later ! 



D. simiata, Java Sea: Thousand Islands (Aurivillius). 



D. trigona, Java Sea: Thousand Islands (Aurivillius). 



D. angulata, Java Sea : Thousand Islands (Aurivillius). 



D. aperta, Java Sea: Thousand Islands (Aurivillius). 



D. cuneata, Java Sea: Thousand Islands (Aurivillius). 



D. Mamdroni, Sumatra (Gruvel). 



D. bitllata, Java Sea : Thousand Islands (Aurivillius). 



The seven species of Aurivillius enumerated in the above list were all of them taken 

 from one and the same stranded specimen of a Palinurus spec. They were found attached to 

 the branchiae or to the interior wall of the branchial cavity of that crayfish. The name of the 

 species of Palinurus is not given, but it is no doubt permitted to suppose that it was a littoral 

 form — no deep-sea species. DicJielaspis Maindroni, the species described by Gruvel, was also 

 found attached to a Palinurus (whether all of them, or only those collected by Mr. Maindron 

 is not distinctly indicated by Gruvel) and also seems to be a littoral form. For D. JVarzaicki, 

 pelbicida and Grayi no definite data with regard to their bathymetrical distribution could be 

 given by Darwin. They are most probably all of them littoral forms : D. Warwicki was found 

 attached to a crab, Grayi to the skin of a sea-snake, and pelhicida also to a sea-snake — they 

 are most probably forms which live at the surface of the sea. D. equina lives on shallow-water 

 crabs and likewise D. ocelusa. 



The species collected by H. M. S. "Siboga" were found at different depths: 



Dichelaspis Tydemani n. sp. at a depth of lo — 25 m. 

 Dichelaspis Versluysi n. sp. at a depth of 22 — 32 m. 

 Dichelaspis Nierstraszi n. sp. at a depth of 27 — 59 m. 

 Dichelaspis orthogonia Darwin at a depth of 88 — 112 m. 

 Dichelaspis Weberi n. sp. at a depth of 560 m. 



The last-named is thus the only true deep-sea species of the collection, and as will be 

 seen from the description it is the largest of the known species. This is a peculiarity which also 

 holds good for many other deep-sea species of Cirripedia (e. g. Scalpellum- and F(?;'r?/r«-species). 



The other known deep-sea species of this genus (D. scssilis) was collected by the Challenger 

 near the Azores at a depth of about 1800 m. All the other species are littoral forms, living 

 at the surface or going down to depths of 30, 50, 100 m. at most. In accordance with this 



