202 BLIND VERTEBRATES AND THEIR EYES. 



This species is everywhere abundant and may attack the fishes if it succeed 

 in attaching itself to them. I have not caught any fish with them attached, but 

 in small aquaria in which many of them were placed as food for the fishes they 

 soon turned the tables and fastened themselves upon the fishes. In some of the 

 caves cirolanas exist in vast numbers. At the base of the shaft of Tranquilidad 

 they were so numerous and voracious that it was impossible to stand in water 

 long enough to light our lamp. They fastened themselves in numbers on the feet 

 and went to work with such a will that it was impossible to stand still. 



Palaemonetes eigenmanni Hay. 



This extremely slender and graceful shrimp is abundant in all the caves. It is 

 essentially pelagic in habit, though it is frequently seen resting on various objects 

 on the bottom. Its eyes have been described by Pike. The species was described 

 as follows in the Proceedings of the U. S. National Museum: 



Carapace thin, very delicate and transparent, in form slightly compressed near the middle of 

 the body but rather broad anteriorly; the anterior border, below the eye, is produced as a broad, 

 obtuse angle, which bears, near its lower margin, an acute, forwardly directed spine; this spine is 

 the anterior end of an obscurely marked ridge, which extends obliquely downward and backward 

 along the sides of the carapace. The rostrum is long, slender, compressed, and rather markedly 

 upcurved ; on its superior margin it bears a row of 6 or 8 slender, acute teeth, which begins well 

 back on the carapace and extends forward to the rostrum ; these teeth are directed obliquely for- 

 ward ; the inferior margin is unarmed ; the tip of the rostrum is acute and reaches forward to a point 

 opposite the distal extremities of the antennal scales. The eyes are much reduced in size, are with- 

 out pigment, and the corneal surface comes to an obtuse point in front. The first antenna has the 

 basal segment well excavated above and provided with a small, acute spine at the outer distal angle ; 

 there are two long and one short flagella, the short one slightly exceeding the rostrum, the long ones 

 somewhat longer than the body. The second antenna has the basal segment provided with a small 

 spine near the distal end ; the antennal scale is broad and with subparallel margins ; the tip is slightly 

 rounded, and there is a small, obtuse spine at the outer distal angle ; the flagellum is slender and 

 about twice as long as the body. The mandible has an incisor portion with three or four sharp teeth, 

 a small molar surface with several obtuse teeth, but is without a palpus. The third maxilliped is 

 not strongly developed and presents no characters of importance. The first pair of pereiopods is 

 chelate, and except for its much smaller size is exactly like the second ; the chela is slender and weak ; 

 the carpal segment is long and slender; the meros is of about the same length, but stouter; the 

 remaining segments short and rather thick. The remaining pereiopods are very long and slender. 

 The abdomen is of the form usual in this genus, but the sixth segment is neither elongate nor com- 

 pressed; the telson narrows gradually from the base to the obtusely angulate tip; on the upper 

 surface there is on each side at about the middle and again about one-fourth the distance from the 

 tip a small, appressed spine; at the tip there is on each side one minute and one long, slender 

 spine, and in the middle a fringe of setae. Color in alcohol, white. Length, 23 mm. 



They differ very markedly from Palcemonetes antrorum Benedict, hitherto our only known blind 

 Palcemonetes, in the shape of the rostrum and the character of the chelae. The shape of the eye is 

 rather remarkable, even in a group, where through atrophy the eye tends toward the conical form. 

 I know of no other in which it is produced into a blunt point. So far as I have been able to ascer- 

 tain, this is the first record for this genus in Cuba. In the material from San Isidro there is one 

 specimen which agrees in every way with the types, but the other two differ in such a manner as to 

 lead me to believe that a second species may be found to inhabit the subterranean waters of Cuba. 

 The two specimens just mentioned have the sixth segment of the abdomen 2.5 times as long as deep, 

 and the antennal scale is more slender and acute. Unfortunately, the rostrum of one is entirely 

 gone, while of the other only the abdomen remains. 



