13 



The pinnies of H. i. laecadivense are 300-400 m long, those of H. i. andam- 

 anense measure 500-600 /^ in length and their distal main-ray bears shorter 

 spines. The dermal macramphidiscs of the subspecies laecadivense are on an 

 averao-e 300 A' lone and 100 /* broad, those of Hyalonema indicum andamanense 

 only 100-130 i^ long and 60-70 a* broad. The ellipsoidal mesamphidiscs with 

 terminal discs so extended as to touch each other more or less completely are 

 larffe and abundant in the latter, smaller and much more scarce in the former. 



The only specimen of Hyalonema indicum laecadivense was found near the 

 Laccadives 11° 12' 47" N., 74° 25' 5" E. in a depth of 1830 m. = l000 fths. The 

 specimen designated as Hyalonema indicum andamanense is somewhat defective, 

 the lower end of the tulip-shaped body and the root-tuft having been torn off. 

 This specimen was found in the Andamans at a depth of 1250 m.=683 fths. 

 It is possible that the sponges provisionally named Hyalonema pirum and 

 H. heymonsi, which will be described below, may be young forms of H. indicum. 



Hyalonema masoni F. E. Sch. 

 Plate V. 



1895 Hyalmetna masoni F. E. Sch. in Abh. Preuss. Ak. 1894 pp. 31-34, Taf. VI. 

 1900 Hyalonema masoni F. E. Sob. iu Abh. Pieiiss. Ak. 1900 p. 8. 



Several of the "Investigator" Hexactinellida belong to that group of 

 Hyalonema-species which is characterised by the presence of micro-oxyhexactines 

 with smooth, strongly-curved rays. The most beautiful of these I have named 

 Hyalonema masoni after the late Professor Wood-Mason, formerly Director of 

 the Indian Museum in Calcutta, who had the great kindness to place all the 

 " Investigator " sponges in my hands for examination. 



The body of the sponge has the shape of a slender, slightly-inflated funnel. 

 It is 12 cm. high and has above, at the upper free margin of the funnel, where 

 it is broadest, a transverse diameter of 65 mm. From the centre of the floor of 

 the funnel-cavity, that is, from the upper surface of the lower solid part of the 

 body, a slender cone, 15 mm. high and 5 mm. thick at the base, rises vertically. 

 The lateral wall of the funnel is at the base, where it rises from the lower solid 

 part of the body, 5-10 mm. thick. Upwards it gradually becomes thinner, and 

 it terminates with a circular, sharp margin (pi. V, f. 1). 



The outer surface is composed of a fine and uniform dermal network, it 

 appears even and smooth. The inner surface is perforated by numerous more or 

 less circular apertures, 1-5 mm. wide, the openings of the excurrent canals into 

 the funnel-cavity which is nothing else than the gastral cavity of the sponge. 

 These canal-mouths are irregularly distributed and decrease in size towards the 

 upper, free margin of the funnel- wall. There is no trace of an oscular sieve- 

 plate. 



