chap, xviii.] MEDIAN UNION: EYES. 461 



717. Helix hispida : specimen in which the tentacles were united 

 together. They were adherent throughout, excepting for a slight 

 cleft at the end, about one line in length. A shallow longitudinal 

 suture was visible between the two. The animal and shell were 

 otherwise normally formed. Roberts, G., Science Gossip, 1886, 

 xxii. p. 259. 

 *718. Apis mellifica (Honey-bee): a worker having the two com- 

 pound eyes continued up so as to unite on the top of the head 

 (Fig. 148). The union between the eyes of the two sides was com- 

 plete. There was no trace of any groove or division between them 

 and the resulting structure was perfectly symmetrical. In a 

 normal the three simple eyes are arranged in a triangle between 



CE~~~^1 



Fig. 148. A worker Bee (Apis mellifica) No. 708, having the two compound 

 eyes united across the middle line, seen from in front, and from the side. 

 CE, the united compound eyes. Oc, a single structure representing the three 

 simple eyes of the normal. (After Stannius.) 



the upper edges of the compound eyes, but in this specimen they 

 were united into a single structure which was symmetrically placed 

 in the middle line in front of the united compound eyes (Fig, 148, 

 Oc). The body thus formed by the union of the simple eyes was 

 a round projection beset with long yellowish hairs. 



In a normal male the compound eyes are much larger and are 

 in contact with each other at the top of the head, but the division 

 between them is sharply defined. In a normal worker, however, 

 the compound eyes are widely separated. 



The facetting and the hairs on these eyes were normal and the 

 animal was in all other respects properly formed. STANNIUS, 

 Muller's Arch, Anal Phys., 1835, p. 297, PI. 

 '719. Apis mellifica having the compound eyes completely and 

 symmetrically fused. This individual was either a young and 

 abnormally developed queen, or else a worker. Its structure was in 

 several respects abnormal. The third pair of legs are like those 

 of the workers, as is shewn by the structure of the first joint of 

 the tarsus, the brush of hairs on the outside of the leg is not so 



