4S0 ATELECRINUS. 



ATELECRINUS P. H. Carpenter, 1881. 



1S69. Antedon Pourtales (pars), Bull. Mus. Comp. Zool., 1, p. 356. 

 1878. " Pourtales (pars), Bull. Mus. Comp. Zool., 5, p. 214. 



1881. Atelecrinus P. H. Carpenter, Bull. Mus. Comp. Zool., 9, p. 16. 



1882. " P. H. Carpenter, Journ. Linn. Soc. London (Zool.), 16, p. 4S8. 

 1888. " P. H. Carpenter, Chall. Rep., 26, p. 68. 



Seit der Zeit, dass Carpenter dieser hoch interessanten Gattung im Challen- 

 ger Report eine eingehende Besprechung widmete, ist Neues iiber dieselbe nicht 

 gebracht worden. Da aber die von Carpenter hinterlassenen Tafeln zur Bear- 

 beitung der Blake-Crinoiden Copieen der bereits 1881, 1. c, veroffentlichten 

 Figuren von A. balanoides und cubensis enthalten (unsere Tafel 6), scheint es 

 Carpenters Absicht gewesen zu sein, nochmals auf die Gattung zuriickzu- 

 kommen. Auch konnte er dies kaum umgehen, weil die Blake-Expedition 8 

 Exemplare von A. balanoides sammelte, und dies Material bei Weitem die 

 wesentlichste Grundlage seiner bereits publicirten Beschreibungen gebildet 

 hatte. Da mir nach Carpenters Tode nur ein geringer Bruchtheil seines 

 Materials iiberwiesen wurde, beschranke ich mich darauf, Carpenters 1882-1888, 

 1. c, gegebenen Beschreibungen hier auszugweise zu citiren. Seine Definition 

 des Genus lautet: 



" Centrodorsal acorn-shaped, and bearing five vertical double rows of cirrus sockets, those of 

 each row alternating with one another, and with those of adjoining rows. They have horseshoe- 

 shaped rims, the arches of which are directed upwards while the two ends slant downwards and 

 outwards. Radials separated from the centrodorsal by a complete circlet of basals. The first 

 six or more brachials bear no pinnules" (1SS1 and 1888). 



Ferner schreibt Carpenter: 



"Three species of this interesting genus are known, two from the Atlantic and one from the 

 Pacific Ocean. One (A. cubensis) was dredged near Havana in 186S, by the U. S. Gulfstream 

 Expedition, though its irregular characters were not then recognized. A second species (A. bala- 

 noides) was first obtained by the 'Challenger' (1873) in the Atlantic, somewhat to the south of 

 Pernambuco. It was subsequently found off the north coast of Cuba by the U. S. steamer 

 'Blake' (1877-78) and again at four stations in the Caribbean Sea by the 'Blake' Expedition 

 of 1878-79. The remaining species (A. wyvilli) was dredged by the 'Challenger' in the neigh- 

 borhood of the Fiji Islands" (1881, 1. c). 



" From a morphological point of view, Atelecrinus is by far the most interesting of all the free 

 Crinoids" (1881, 1. c). 



"Its two leading characters are: (1) the persistence of the embryonic basals which do not un- 

 dergo transformation into a rosette, but remain on the exterior of the calyx between the centro- 

 dorsal and the radials; and (2) the absence of pinnules from the lowest joints of the arm. A third 

 character, of no great morphological value, but important from its apparent constancy, is the 

 acorn shape of the centrodorsal, and the arrangement of the cirrus sockets upon it in alternating 

 double rows with the ends of their horseshoe-like rims projecting somewhat outwards" (1888, 1. c). 



"The extent of development of the basals of Atelecrinus varies with the size of the individual, 

 apparently diminishing with age as in the Pentacrinoid larvae of ordinary Comatulae. In the 

 smallest specimen of Atelecrinus balanoides they are wide but low pentagons which fall away very 

 rapidly from their interradial apices to the points where they meet one another beneath the radials. 



