1^11] Michael: Chactognatha of the 8an Diego Region. 41 



In comparing the San Diego specimens with those which 

 Fowler (1905) obtained, we notice a great difference in number 

 of anterior and posterior teeth. He records from 3 to 7 an- 

 terior and 3 to 13 posterior teeth in individuals ranging from 

 5 to 15 mm. in length. For a length of 13-14 mm. he finds 5 to 

 7 anterior and 8 to 12 posterior teeth. The specimens from San 

 Diego, therefore, present a greater number of teeth for the same 

 length of individual. 



Sagitta bipunctata Quoy et Gaimard 



PI. 1, fig. 5; pi. 3, figs. 18, 19; pi. 4, figs. 31, 32; pi. 5, fig. 40. 



Sagitta hipiutctnta Quoy et Gaimard (1827), p. 232; Busk (1856), 

 p. 16; Hertwig (1880), p. 258; Strodtmann (1892), p. 344; 

 Fowler (1905), p. 69, (1906), p. 31; Ritter-Zahony (1908), p. 15. 



Sagitta sp. innom., Oersted (1849), p. 26. 



Sagitta multidentata Krohn (1853), p. 271. 



Sagitta germanica Leuckart und Pagensteclier (1858), p. 593; 

 Uljanin (1871), p. 77. 



Sagitta setosa Keferstein (1862), p. 135. 



Spadella bipunctata, Grassi (1883), p. 13. 



Spadella mariona Gourret (1884), p. 103. 



Spadella hamata, Aurivillius (1898), p. 117. 



Sagitta decipiens, Michael (1908), p. 68. 



Sagitta pulchra, Michael (1908), p. 68. 



'Sagitta bipunctata forma typica Ritter-Zahony (1910), p. 255. 



General Appearance 



This species is only slightly more opaque than 8. enflata, 

 but appears to the naked eye somewhat narrower, more rigid, 

 and of more uniform width from head to tail. When on a black 

 background (pi. 1, fig. 5) the head, intestine, ventral ganglion, 

 ovaries, seminal vesicles, and tail present a distinct, though 

 rather less, contrast to the body proper than is the case with 

 8. enflata. 



Characters 



Body rigid, retaining its form well. Neck nearly, if not quite absent. 

 Body widest usually behind middle, but varies from 40 to 60 per cent. 

 It tapers very gradually forward and backward from this point. Lateral 

 fields large. Muscles thin and weak but stronger than those of S. enflata, 

 the strands being barely visible under a dissecting lens. Constriction 

 at tail-septum evident. Collarette present but very short. 



Anterior fin never extends forward to ventral ganglion. Interval 

 between fin and ganglion usually about 7 per cent, but varies from 4 

 to 10 per cent. Fin rather triangular in form. 



