186 TYLODINA. 



T. CITRINA Joannis. PI. 73, figs. 77, 78, 79, 80, 81, 82, 83. 



Shell short-oval, low-conic, rather thin ; apex subcentral, directed 

 slightly backward and to the left ; surface smooth, showing slight 

 growth lines under the lens, a peripheral zone 3 or 4 mill, wide is 

 membranaceous and squamose. Color pale yellowish, deeper toward 

 the apex, with a variable number (6 to 22) of red-brown radial 

 bands, coloring the cuticle, unevenly spaced, sometimes part of them 

 disposed in pairs ; apex whitish. The dark rays do not reach the 

 apex, and are entirely epidermal, worn shells not showing them. 



Length 20, breadth 15, alt. 4 mill. 



Soft parts citron-yellow throughout, with slightly paler bands on 

 upper surface of the foot ; gill pale yellow. Gizzard armed with a 

 multitude of corneous, lamellose denticles. Jaws represented by 

 fleshy prominences on each side of the mouth, covered with a trans 

 parent chitinous cuticle. Kadula with the formula 80 to 130.1.80 to 

 130 ; usually about 90.1.90. 



Bay of Athens (Joannis) ; Palermo and Catania, Sicily (Arad. & 

 Ben.) ; Sardinia (Cantraine) ; St. Helena (Smith) ; Lancerotte, Ca- 

 naries (McAndrew). 



Tylodina citrina JOANNIS, Mag. de Zool., 1834, pi. 36, f. 1-5. 

 WEINKAUFF, Conch, des Mittelm. p. 178. ARAD. & BEN., Conch, 

 viv. Mar. Si cilia, p. 123. MONTS., Nuova Kivista Conch. Medit., p. 

 49. KOBELT, Prod. Faun. Moll. Eur., p. 273. Tylodina (Joannisia) 

 citrina MONTS., Nomencl. Gen. e Spec. Conch. Med., p. 149. VAYS- 

 SIERE, Ann. Sci. Nat. (6), xv, 1883, p. 28, pi. 2, 3, f. 22-35; Re- 

 cherches Zool., Opistobr., p. 152, pi. 5, f. 130-136. SMITH, P.Z.S., 

 1890, p. 299. T. punctulata Raf., GRAY, P. Z. 8., 1856, p. 46. 



? Parmophorus patelloideus CANTRAINE, Bull. Acad. Brux., ii, p. 

 395._ Umbrella patelloidea CANTR., Malac. Medit. et. Lit., p. 93 [pi. 

 8, f. 19?]. 



? Tylodina punctulata RAFINESQUE, Journ. de Physique, de Chimie, 

 d'Hist. Nat., etc., Ixxxix, 1819, p. 153. 



?T. atlantica GRAY, P. Z. S., 1856, p. 46=" Umbrella (small)," MC- 

 ANDREW, Ann. Mag. Nat. Hist. (2), x, p. 104. 



The shell is larger and more depressed than in T. rafinesquii 

 Phil. 



It is uncertain which species of Tylodina was known to Rafines- 

 que. His description is as follows : 



"Genre 5. TYLODINA. (Mollusque). Corps rampant, a petite 

 coquille dorsale exterieure membraneuse, sans spire, oval, a pointe 



