316* CONTRIBUTIONS TO THE NATURAL HISTORY OF THE ACALEPH^. 



Plate VII. — Staurophora laciniata. 



Fio-. I to II represent natural attitudes of this remarkable species, of natural size in Fig. 1 to 8, and somewhat 

 enlarged in Fig. 9 to 11. 



Fio-. 1. From the side, somewhat contracted, in a state of onward movement, tlie marginal tentacles being drawn to- 

 gether and hanging backwards. 



Fig. 2. From below, the margin being folded over like four lobes. 



Fig. 3. A profile view, in an attitude in which the gelatinous disk is considerably raised. 



Fig. 4. From above, the lower margin being contracted inwards. 



Fig. 5. In the same position, the lower margin assuming a quadrangular outline. 



Fig. 6. Swimming downwards, the margin contracted in a circular outline, and the tentacles drawn inwards. 



Fig. 7. The lower margin is here stretched outwards in undulating lobes, seen from below. 



Fio-. 8. We have here a view from above, the whole animal assuming a more quadrangular shape. 



Fig. 9. Magnified view of the animal seen from above, the curled tentacles stretching outwards. Small eye-specks are 

 seen upon their swollen bases ; but what is most prominent is the central cross formed by the radiating tubes, and the ex- 

 tensive fringes encircling the star-shaped mouth. 



Fig. 10. A profile view of the same animal, the cross being placed so that two radiating tubes appear on the right, and 

 two on the left. 



Fig. 11. Another profile of the same, the radiating tubes being placed in a different position. Two small specimens of 

 Sarsia are caught between the fringes of the mouth in two opposite parts of its extensive cross. 



Fio-. 12. The central space of the mouth with four radiating furrows encircled by membranous folds. 



Fig. 13 shows in a profile view the origin of the closed radiating tubes, beyond the edge of the mouth, the folds of 

 which hang below, and some eggs above. 



Fig. 14. The same region seen from below, to show how the furrow of the mouth passes into a closed radiating tube. 



Fig. 15. The central part of the mouth, with its four radiating furrows. 



Fig. 16. The lower margin of the animal near a radiating lube, two tentacles hanging down, one curled upon itself, 

 and the other cut at its extremity, and two equally cut near their base, lifted up to show that the eye-specks are upon the 

 inner surface of the tentacles. 



Plate VIII. 



Ideal sections of all the genera illustrated in this paper. The illustrations in all the figures correspond to each other to 

 facilitate comparisons. 



In Fig. 1 and 4, a, a represent the lower centre of the gelatinous disk ; b, b, its main bulb ; c, c, its lateral wall. 



In Fig. 2, 3, 5, 6, 11, and 12, a indicates the main internal vertical bundles ; b, the main external vertical bundles ; 

 c, the circular bundles ; d, the nervous cord ; e, the upper nervous cord ; g, the nervous plexus ; i, the circular tube ; 

 h, the tentacles ; k, the lower partition ; /, the vertical tubes. 



In Fig. 7 and 9, a, a indicate the inner circular muscles ; b, h, the main external vertical muscles ; V, b', the secondary 

 vertical external muscles; c, c, the main inner vertical muscles; c', c', the secondary inner vertical muscles ; /, t, the 

 vertical tubes. 



In Fig. 8 and 10, a indicates the lower partition ; b, the nervous cord ; c, the circular chymiferous tube ; d, the sensi- 

 tive bulb ; e, the outer main vertical bundles ; e' , the inner main vertical bundles ; t, the radiating tubes. 



Errata. —Page 285, line 10 from bottom, erase/,/. —P. 298, line 6 from bottom, read Fig. 6, instead of Fig. 5. 



