FAUNA OF THE OUTEK WESTERN APtEA OF THE CHANNEL. 319 



range in the first specimen from 190 jj. to 220 /j. in length, by about 3 /x 

 in width. In the second specimen they are longer and much more 

 slender on the average, about 220 by 2 jx. Spined tylostyli are 

 extremely scarce, one only, in fact, having been observed in one speci- 

 men, and none in the other. This spicule has the characteristic 

 prominent head, and measures about 92 ^. Embryos are present in 

 both specimens ; several in one case, irregularly located. In a few 

 instances the tylota have a prominent bulbous swelling at the centre, or 

 some way from one end. The proportions of the spicules seem very 

 instable in this species. In a specimen obtained from within two miles 

 of the Eddystone Lighthouse they average about 185 ^ (many falling to 

 120 yoi) by 1-5 /x, or less, while in a preparation of another specimen 

 only a few are to be found at all. 



BUBABINAE, Topsent. 

 Bubaris vermiculata (Bowerbank). 



At Position 15 (four), 38, 43, 44 (two), 47 (five), 59, 60. 



Depth, 44-49 fath. 



The examples have all the form of a thin cementing investment about 

 dead valves and fragments of Pcden, Cardium, Lima, etc., and larger or 

 smaller pebbles. The maximum extent ranges from 9 to 45 mm. 



ECTYONINAE, Kidley and Dendy. 

 Stylostichon plumosum (Montagu). 



At Position 10, one specimen, forming an irregular growth coating 

 tubes of Pallasia murata, etc. Measurement, 

 85 X 45 X 25 mm. 

 „ 49, one specimen, forming a nodulous investing growth, 

 cementing together shell fragments and gravel, 

 with CeUaria, etc. Measurement, 50 x 33 x 20 

 mm. 

 Depth, 42-47 fath. 



Acanthoshjli: Large, 180-280 ju (average about 226 /m.) in length, 

 and 5-5-7 '4 jn (average about 7'2 /m) in width. Small, 85-160 fi (average 

 about 120 /ui) in length, and 5-5-7'4 /m (average about 6-8 /j.) in width. 

 There is no distinct line of separation between these and the pre- 

 ceding. 



Oxca. Straight, suddenly pointed: 185-207 /u (average 195 /n) in 

 length, and 3-5-5"5 fx (average 5 jul) in width. 

 Lsochelae. Mostly bidentate, but many tridentate : 14'5-18"5 fx. 

 Bowerbank mentions this coating variety, thinly investing stones, from 

 the Diamond Grounds, off Hastings. 



