294 Dr. Philippi on Pandorina coruacans. 



XXXIII. — Zoological Notices. By Dr. A. Philippi*. With 



Plates III. and IV. 



[Continued from p. 9(>.] 

 6. Pandorina coruscans, Scacchi. Plate IV. fig. 1 — 4. 

 Sr. Arcangelo Scacchi has described this remarkable 

 genus in his e Osservazioni Zoologiche/ p. 14 (May 1833), in 

 the following words : " Testa bivalvi, transversim oblonga, 

 alba ; latere antico (i. e. anali) productiore, truncato, hiante ; 

 postico (i. e. orali) rotundato ; valvis inaequalibus, fragilissimis, 

 subpellucidis, intus margaritarum nitore coruscantibus, ex- 

 terius ad ambitum tenuissimo epidermide obductis, longitu- 

 dinaliter striatis, ad umbones laeviusculis ; striis transversis 

 obsoletis ; valva dextra (i. e. sinistra) majore, umbone ac limbo 

 superiore (i. e. ventrali) sinistram superante ; valva sinistra 

 (i. e. dextra, si animal incedens inspicitur) inferius ad latus an- 

 ticum (i. e. posticum) super dextram producta ; membrana 

 praetenui ad latera umbonum valvas revinciente ; cardine eden- 

 tulo ; linea prominula obliqua pro ligamenti insertione ; liga- 

 mento tantum interno oblongo ; ultra pollicem lata, altitu- 

 dine 5 lin." To this description I have only the following 

 remarks to add. The longitudinal striae are extremely deli- 

 cate, elevated, and every fourth is as it were beset with small 

 points, which proceed from the epidermis. The membrane, 

 which unites posteriorly the dorsal margin of the shells, I 

 would without hesitation call an external ligament. An area 

 and a lunula may be distinguished, which are rather sharply 

 defined, and are smoother than the rest of the shell : both are 

 narrow and asvmmetrical ; the lunula is broader on the left 

 shell, the area on the right. The muscular impressions are 

 tolerably near to the margin ; the anterior one is longitudi- 

 nally oval, the posterior one more quadrate and far nearer to 

 the margin on the left shell than on the right, which corre- 

 sponds to the line denning the area. The impression of the 

 mantle has a very slight incurvation, which forms nearly a 

 right angle with the part of the shell parallel to its ventral 

 margin. This indicates two very short tubes, which the ani- 

 mal actually possesses. The hinge is quite toothless ; never- 



• Translated from Wiegmann's < Archiv,' Part 2. 1839.— The Plates will 

 be given next month, in the Supplement. 



