SILICIOUS AND HORNY SPONGES WILSON. 437 



occur; in addition, toxas, sigmas, trichodragmas or bundles of 

 stouter microxeas may also occur. 



Ridley and Dendy, 1887, redefined Hamacantha Gray and Vomer- 

 ula Schmidt, making the distinction to lie in the shape of the mega- 

 scleres, oxeate in the former, stylote in the latter. Topsent, 1894c 

 (p. 7), combined the two genera on the ground that the megascleres 

 vary within the same species. Vosmaer (1887) had previously used 

 Hamacantha in this extended sense, reserving Vomerula Schmidt 

 for forms like V. tibicen O. Schmidt (1880, p. 83) possessing dian- 

 cistra and chelas (Vosmaer lists, as an example, V. tenda O. 

 Schmidt, evidently a slip, since the definition shows he had in mind 

 Schmidt's second species, V. tibicen. Topsent has recently, 192(M, 

 (p. 9) redescribed V. tenda.) But since no one has rediscovered 

 forms with diancistra and chelas, Ridley and Dendy 's criticism 

 (1887, p. lxvi) of Vomerula tibicen Schmidt has been followed, and 

 the species, and with it, Voinerula in the sense of Vosmaer 1887, 

 deleted. Hamacantha in the present sense remains as the sole genus 

 of the subfamily. 



Lundbeck, 1902 (p. 108), enumerates the known species, to which 

 Topsent especially (1904) has added a number of others from the 

 region of the Azores. Hamacantha is a genus of sufficient com- 

 plexity to be set apart from simpler forms such as the Gelliinae, 

 Renierinae, etc., along with which Ridley and Dendy, 1887, classed 

 it. Topsent, 1894c, accordingly transferred it to his Poeciloscleridae 

 (Desmacidonidae authors) . Some others, however, Kirkpatrick, 1911, 

 and Dend}', 19215 (p. 25), would retain the genus (or subfamily) 

 in the Haploscleridae. 



HAMACANTHA ESPERIOIDES (Ridley and Dendy), var. MINDANAENSIS, new variety. 



Vomerula esperioidcs Ridley and Dendy, 1887, p. 60. 

 Hamacantha esperioides Kirkpatrick, 1903, p. 253. 



One specimen from station D5504 (off the island of Mindanao). 



Ridley and Dendy's species was based on a number of large, erect 

 sponges from the South Atlantic (Agulhas Bank and off Rio de la 

 Plata). Surface conulose; dermal membrane reticular to the e3 7 e. 

 Main skeleton a coarse reticulum of thick stout spiculo-fiber; dermal 

 skeleton in general a reticulation of spiculo-fiber. Megascleres : styles, 

 smooth, slightly curved, tapering at both ends, 700 by 19 y.. Micro- 

 scleres: large diancistra 177 |x long and sigmas 38 \i long. A small 

 type of diancistron, regarded as perhaps a young form, of about 

 same length as the sigma is also recorded. II. esperioides has also 

 been taken southeast of Cape Colony (Kirkpatrick, 1903, p. 253.) 



