TUREIS FONTATA. 211 



their length ; these diverticulae (PI. 42, fig. 5) may or may not be branched, 

 as Hartlaub ('92) has described them for T. coeca. The circular canal bears 

 no diverticulae, though its margin is somewhat jagged (PI. 42, fig. 5). The 

 canals are very deep basally, their inner faces being connected in the per- 

 radii with the walls of the manubrium. It was this conformation of the 

 canals in various Tiaridae which was responsible for Haeckel's description 

 of mesenteries; his interpretation was shown by Vanhoffen ('91) and by 

 Hartlaub ('92) to be erroneous. 



Gonads. — The gonads are typical of the genus. Each consists (PI. 39, 

 fig. 8) of two adradial series of transverse folds, often subdivided into two 

 hree, or even more minor folds ; the two series are connected in the interradii, 

 throughout their length by a scattered development of ova, and at the base 

 of the manubrium by a series of irregular folds. In the perradii, the two 

 adjacent series of folds are closely in contact, but separated by a narrow zone 

 in which no ova are developed. They thus closely resemble, except for 

 rather greater complexity and irregularity, the description and figure given 

 by Hartlaub ('92) of the sexual organs in the Mediterranean and Atlantic 

 T. coeca. 



Color. — In life the gonads were deep orange ; manubrium and tentacles 

 pale ochre yellow ; bell bluish, hyaline. 



All members of the genus Turris are closely allied. T.fontata in general 

 closely resembles both of the Pacific species, T. pelagica and T. brevicornis, yet 

 is distinguishable by several characters. It differs from both in its greater 

 development of glandular diverticulae of the radial canals, and in the fact 

 that these are often branched, for though diverticulae are described for both 

 T.pelagica( Agassi z and Mayer, : 02) and T. brevicornis (Murbach and Shearer, 

 : 03), in both they are short and simple. From both, moreover, it differs 

 in the marginal organs and in color. T. pelagica and T. brevicornis have 

 all the tentacles alike ; and although it is true that the present species might 

 perhaps arrive at such a condition, did its growth and that of the rudimen- 

 tary tentacles continue far enough, yet we have no right to assume that this 

 is the case in view of the advanced condition of its gonads. The presence 

 of pigment spots at the bases of the rudimentary tentacles, even if not of 

 distinct ocelli, is a further characteristic feature, although we must bear in 

 mind that did all the rudimentary bulbs develop into tentacles these pigment 

 spots would probably be lost. Furthermore, and most important, in no 

 other species of the genus have tentacular ostia or exumbral sense-pits 



