524 DR. G. HERBERT FOWLER ON THE [May 18, 



Scolopendra, Kef. One on the neuropodium only; pigment 

 dark red ; two lenses. 



Onisciformis, Esch. Two on the notopodium, two on the neuro- 

 podiurn ; pigment yellow ; five lenses. 



These seem good diagnostic characters, but are unfortunately 

 not entirely justified. 



Taking first the number and position of these organs, and 

 accepting Vejdovsk^'s and Keferstein's account of vitrina and 

 scolopendra respectively, the alleged presence of two "Elossenaugen" 

 on each half of the parapodium in onisciformis is stated by Vej- 

 dovskf to have been observed by Carpenter and Claparede \ and 

 by Leuckart and Pagenstecher 2 . A reference to the original 

 memoirs shows, however, that the first-named authors describe and 

 figure one only on the notopodium, one on the neuropodium ; and 

 that the German authors, describing a 2 mm. onisciformis under 

 the name of quadricornis, describe and figure one only on the 

 basal part of each parapodium. Busch 3 also, in describing young 

 specimens, agrees with Leuckart and Pagenstecher. Tomopteris 

 onisciformis, therefore, like T. vitrina, has apparently one " Elossen- 

 auge " on the notopodium, one on the neuropodium, or two on 

 each parapodium ; it has probably only one in young stages, and 

 this only on certain parapodia. 



Taking next the question of the pigment, its colour, yellow, 

 dark red, or brown, can hardly be reckoned diagnostic. Lastly, 

 with regard to the question of the lenses these appear, according 

 to Greef 4 , who worked on fresh material at the Canary Islands, to 

 be artificial products of the preservation fluids. Almost certainly, 

 judged by a comparison of the figures, the five lenses attributed by 

 Vejdovsk^ to Leuckart and Pagenstecher's onisciformis are the 

 same things as his " Augen-driise " cells, which appear to surround 

 the pigment-cells in a surface view. 



There^ seems, therefore, to be no real specific distinction between 

 Vejdovsk^'s vitrina and onisciformis (auctt.). In my specimens of 

 onisciformis the basal joint of the second cirrhi (Borstencirrhen) 

 was sometimes longer, sometimes shorter than the first parapodium, 

 and the eye-lenses were single thus breaking down two more of 

 his diagnostic criteria. 



It is possible, as Vejdovsky suggests, that T. scolopendra (Kef.) 

 may be separate from T. onisciformis C?=Briarcea scolopendra, 

 Quoy and Gaimard 5 ) ; but it is always difficult, often impossible, 

 to make certain of the " Elossenaugen " in preserved material, 

 and conceivably scolopendra may prove a Mediterranean variety of 

 onisciformis. 



The largest ' E-esearch ' specimen measured 45 '5 mm. in length ; 



1 Trans. Lirmean Soc., xxiii. p. 59. 



2 Arch. Anat. Physiol., 1858, p. 588. 



3 Arch. Anat. Physiol., 1847, p. 180. 



4 Zeitschrift wiss. Zoologie, xxxii. p. 237. 



5 Ann. Sciences naturelles, x. p. 235. 



