1903] Collins, — The Ulvaceae of North America | 31 
U. Hopxirki Pike (1) 106. 
U. iNTESTINALIS Anderson (1) 218. 
U. Lacruca Bailey (1) 402. Curtis (1) 156. Hall (1) 112. 
Pike (1) 106. 
U. Lacruca var. Lacruca Pike (1) 106. Bennett (1) gs. 
U. Lactuca var. LATISSIMA Howe (1) 167. 
U. LACTUCA var. RIGIDA Pike (1) 106. 
U. LATISSIMA Postels & Ruprecht (1) 21. Bailey (1) 402. Hooper 
(1) 3o. Hall (1) 112. 
ENTEROMORPHA CLATHRATA Hooper (1) 30. Kemp (1) qr. 
Olney(1) 9. 
E. COMPREsSA Postels & Ruprecht (1) 21. Bailey (1) 402. Hooper 
(1) 3o. Bailey & Harvey (1) 163. Hervey (2) 176. Ashmead 
(2) 96. Curtis (1) 156. Kemp (1) 41. Harvey (1) 50. Eaton 
(1) 348; (2) s. Melvill (1) 265. Hall (1) 112. Murray (1) 260. 
Olney (1) 9. Wolle (1) 107. Fowler (1) 48. 
E. ERECTA Hooper (1) 30. Olney (1) 42. Bailey (1) 402. 
E. INTESTINALIS Bailey (1) 402. Hooper (1) 3o. Harvey (2) 
176. Curtis (1) 156. Kemp (1) 41. Olney (1) 42. Wolle (1) 
107. 
MONOSTROMA PULCHRUM Pike (1) 106. Martindale (1) 92. 
M. BLvri1 Martindale (1) 92. 
EXPLANATION OF PLATES. — Plate 41. Fig. 1, Ulva Lactuca var. rigida. 
Figs. 2, 3, Monostroma fuscum forma Blyttii. Figs. 4,5, M. Greviller. Figs. 
6, 7, M. arcticum. Figs. 8, 9, M. pulchrum. Figs. 10, 11, M. leptodermum. 
Figs. 12, 13, M. undulatum. Figs. 14, 15, M. crepidinum. Figs. 16, 17, M. 
quaternarium. Figs. 18, 19, M. latissimum. Figs. 20, 21, M. Groenlandi- 
cum. Figs. 22, 23,24, flea fulvescens. 
Plate 42. Figs. 1, 2, Enteromorpha micrococca. Fig. 3, E. flexuosa. Fig. 
4, E. torta. Fig. 5, E. prolifera. Figs. 6, 7, E. intestinalis. Fig. 8, £. 
Linza. Figs. 9, 10, E. minima. Figs. 11, 12, E. compressa. Fig. 13, E. 
marginata. Fig. 14, E. crinita. Figs. 15, 16, E. percursa. 
Plate 43. Fig. 1, Enteromorpha cruciata. Fig. 2, E. erecta. Fig. 3, E. 
Hopkirkit. Fig. 4, E. clathrata. Fig. 5, E. acanthophora. Fig. 6, E. 
ramulosa. 
MALDEN, MASSACHUSETTS. 
